Separation phenomena for gaseous mixture flowing through a long tube into vacuum

摘要

A gaseous mixture flow through a long tube into vacuum is considered assuming the pressure to be arbitrary at the tube entrance. Thus, the flow regime can vary from hydrodynamic at the entrance to free molecular at the tube exit. The distributions of density and concentration along the tube were obtained for the mixture helium-xenon at various values of the concentration and rarefaction at the tube entrance. It was shown that the variation of the concentration along the tube can be significant. The flow rates of both species determining the chemical composition in the down flow container were calculated. An analysis of these data shows that the chemical composition in the down flow container can be different from that in the up flow one, i.e., the separation phenomenon takes place. The results presented in the article can be used in practice to avoid the separation phenomenon or to intensify it if necessary.